The new commissioner of the Metropolitan police has announced key changes to its stop and search policy, saying the force had to use the powers in a "smarter" way.

Bernard Hogan-Howe, appearing at the Metropolitan Police Authority (MPA) for the first time, was challenged about the widespread use of stop and search by the London force and about fears that this had triggered the anger in communities in areas such as Tottenham, which saw rioting last month.

Hogan-Howe, who officially takes over the force on 26 September, appeared to decide under questioning today that the policy should change.

The incoming commissioner – who set up the Matrix operation against guns in Liverpool while chief constable of the Merseyside force – said stop and search powers were important to the police, but by December this year the Met should be using them in a more targeted way.

"There are changes that can be made in its use," he said. "We should in future target more people who have previously been convicted of offences involving guns and knives. We need to make sure we are targeting them when they are on the streets rather than just carrying out generic stop and search."

Hogan-Howe said he was confident that Londoners would come forward with details of those who were carrying guns or knives, adding that what was needed was a mass publicity campaign to ensure the 8 million-strong population in the capital knew they could phone a number to report someone carrying a weapon. "That cannot be that difficult," he said.

"We need to establish the machinery whereby we get into the public's mind that if they ring a number they can report who is carrying a knife, what car they are driving and we will do the rest.

"We need to move away from searching in an area to searching for a person, and stop targeting the people who don't need to be targeted."

Asked by Jenny Jones, the Green party representative on the MPA, when the public would be likely to see these changes in place, Hogan-Howe said by December.

Jones said that in her meetings in Tottenham, north London, the widespread use of stop and search had been cited as a reason why so many people were angry. The MPA was also told that a review by the Met of its policing in the runup to and during the riots was examining whether Operation Target, a visible clampdown on robbery and burglary – both of which are rising in London – which used stop and search, had played any part in exacerbating tensions in certain inner-city areas.

Hogan-Howe said: "I think there are people out there who are prepared to work with us. We have got to be smarter about how we respond and use this power."